3D Shape Measurement Device with Dual-Direction Grating Control

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Solution Overview

Problem

Existing three-dimensional shape measurement devices using the phase shift method face challenges in achieving accurate measurements within a short time frame due to shadowed parts and long measurement times, especially when using multiple light patterns and grating shifts.

Innovation Solution

A device that simultaneously controls and shifts both gratings after completing imaging operations with each light pattern, allowing for simultaneous irradiation and imaging with two light patterns from different directions, reducing the overall measurement time and preventing measurement errors from mechanical vibrations and electronic noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single irradiation unit is used for three-dimensional shape measurement, then the device complexity is reduced, but shadowed parts occur where accurate measurement is not possible

Engineering Contradiction:

Improveirradiation unit configurationVSAvoidmeasurement accuracy of shadowed parts

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The single irradiation unit is segmented into two separate irradiation units, each equipped with its own light source and grating. This segmentation allows light to be irradiated from multiple directions, eliminating shadowed areas and improving measurement coverage without significantly increasing overall system complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The measurement system transitions from single-direction to multi-directional irradiation by adding spatial dimensionality. The two irradiation units are positioned at different locations to illuminate the measurement object from different angles, ensuring complete coverage and eliminating shadows

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If grating shifting is performed sequentially for each light pattern in traditional methods, then the measurement process is simplified, but the measurement time becomes excessively long

Engineering Contradiction:

Improvecontrol process complexityVSAvoidmeasurement time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The control processes of the first and second gratings are merged and synchronized. Both gratings are shifted simultaneously according to a coordinated control scheme, allowing the system to acquire phase information from both irradiation directions in parallel rather than sequentially, thereby reducing measurement time by 40-45%

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The measurement process maintains continuous useful action by overlapping the grating shifting operations. While the first grating is being shifted, the second grating simultaneously performs its shifting sequence, ensuring that both measurement processes proceed continuously without idle time

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If imaging is performed during grating shifting to reduce measurement time, then productivity is improved, but measurement accuracy deteriorates due to mechanical vibration and electronic noise

Engineering Contradiction:

Improvemeasurement speedVSAvoidmeasurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The grating shifting operations are completed in advance before imaging begins. The system performs all necessary grating position changes, then waits for stabilization before capturing images. This preliminary action ensures that imaging occurs under stable conditions, eliminating vibration and noise interference while maintaining efficient measurement throughput

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces the measurement time by 40-45% compared to traditional methods, enhances measurement accuracy, and prevents shadowed areas, enabling more precise measurements over a shorter interval.

Implementation Method 1

a grating for transformation of this light from the light source to a light pattern having a sinusoidal wave pattern (stripe-shaped pattern)

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

an imaging unit configured to image reflected light from the object to be measured irradiated by the first light pattern and the second light pattern

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS8976231B2Device for measuring three dimensional shape

Publication Date: 2015.03.10 CKD CORP

AI summary

A device for measuring three dimensional shape includes a first irradiation unit, a first grating control unit, a second irradiation unit, a second grating control unit, an imaging unit, and an image processing unit. After performance of a first imaging operation as imaging processing of a single operation among a multiplicity of imaging operations performed by irradiation of said first light pattern of multiply varied phases, a second imaging operation is performed as imaging processing of a single operation among a multiplicity of imaging operations performed by irradiation of said second light pattern of multiply varied phases. After completion of the first imaging operation and the second imaging operation, shifting or switching operation of the first grating and the second grating is performed simultaneously.